All animal caging systems and installations for keeping and tending animals, such as laboratory test animals, must address ventilation requirements for the cages, cleaning and maintenance of the cages, and feeding and manipulation of the animals in the cages. Often of primary concern in such caging systems is the prevention of cross-infection or cross-contamination between animals in adjacent cages. Yet another and often significant consideration in caging systems in the adaptability of the system to the particular area in which it is located, such as a laboratory, where available space may be at a premium.
Caging systems in the past have attempted to meet many of these noted considerations. For instance, U.S. Pat. No. 3,220,383 discloses a caging system for laboratory test animals which provides for the individual mounting of animal cages in a plenum fixed to an upright surface, i.e, a wall. Each of the individual cages has sockets in its rear wall in which are received pipes extending from the plenum, permitting the attachment and removal of the cages from the plenum. A suction ventilation of the cages is provided that draws air through the cages and out through the plenum to keep the area surrounding the cages fairly free from odors generated by the caged animals.
Although the U.S. Pat. No. 3,320,383 caging installation has desirable features, it suffers from being a wall-mounted installation. In many laboratories, wall space can be a critical commodity and not worth sacrificing to support a caging system such as this. Further, since the U.S. Pat. No. 3,320,383 system is fixed to a wall, it cannot be moved around a laboratory, except through laborious disassembly and reassembly of the system on another wall. It is much more desirable to have a free-standing caging structure which can be moved around from place to place as the need arises.
U.S. Pat. No. 3,924,571 discloses another modular system for caging animals, each cage being separately supplied with a controlled environment. The U.S. Pat. No. 3,924,571 caging system is free-standing, and capable of being easily moved around from place to place, being mounted on wheels. This caging system, however, suffers from the use of a fairly substantial fixed framework housing supporting the various cages. This framework is far more elaborate than that of the U.S. Pat. No. 3,220,383 system, where the simple plenum actually carries the cages.
In brief, there is a need for an environmental chamber apparatus which overcomes the problems or disadvantages associated with current structures. There is also a need for such structures which provide economies in assembly and use.